Lunar helium-3 is considered one of the potential resources for utilization as fuel source for future earth-based nuclear fusion plants. With a potential start-up of a commercial fusion power plant by the year 2050, the author describes technology and commercial aspects for a lunar helium-3 mining operation that could fuel such a power plant. Barriers for development are inferred to exist largely in the fusion portion of the helium-3 value chain. Commercially a helium-3 operation would have to compete with other energy supply sources that might become available in the future and that could be developed in a stepwise function rather than in an all-encompassing effort. The author suggests that space technology RD&D and fusion research should be pursued separately, and should only form a symbiosis once a common fit due to separately achieved scientific/technical progress justify a joint commitment of financial resources. RD&D costs for these programs will be several hundred billion dollars, which will largely be provided by public investments. The private sector, however, is emerging in space technology and could play a significant role in such a value chain, as outlined in the suggested business model.

The Nearside Megabasin, 3,200 km wide and centered on the western half of the Lunar nearside, is inferred to have formed from a giant impact ~4.3 billion years ago. Evidence for the basin include s: radial graben, remnant ring structures, aligned igneous features such as domes and dome fields along remnant rings, a thin (<20- km) depressed crust, and anomalous volatile deposits along zones of structural weakness. The Nearside Megabasin is also associated with the Moon’s greatest concentration of thorium and KREEP (Potassium, Rare-Earth Elements and Phosphorus) lavas that formed from late-stage partial melts, possibly in response to decompression melting following deep excavation of the lower crust and upper mantle from the Procellarum impact event. These thorium deposits and related volatiles are important resources for sustaining future human settlement on the Moon.

The Nearside Megabasin contains the largest continuous extent of lunar basalts on the Moon and its upper fill is a complex of a t least four different flow units, recognized on the basis of albedo and spectral reflectivity. Individually, these flow units are only a few hundreds of meters thick, but may be underlain by 2-4 km thick ba sin-filling basaltic units. In contrast to many other lunar ba sins, the Nearside Megabasin lacks a surrounding mountain rim and underlying mascon, features commonly associated with other nearside lunar basins such as Mare Tranquillitatis, Serenitatis, and Crisium. However, the absence of these features may be due to the basin having formed so early that the lunar crust may have not been sufficiently rigid to support rim material and excess masses of thick basin-filling units.

This articles is adapted from oral presentation at AAPG Convention, Denver, Colorado, June 7-10, 2009.

Mars, Mercury, the Moon, and many satellites of gas giants Jupiter, Saturn, and Uranus, are scarred with giant impact basins that record collisions from asteroids during the early history of the solar system. Giant impact basins, typically hundreds to thousands of kilometers in diameter, are associated with distinctive morphological features, including multiple concentric rings, radially distributed scour valleys, fractures and radial graben, crater chains, and large (>20 km in diameter) secondary craters. Impacts that formed giant basins commonly resulted in deep excavation and fracturing of planetary crusts, forming conduits for later upward migration of magma plumes and subsequent basin infilling with lava. For example, most giant nearside lunar basins that formed between 3.8 an d 4.3 billion years ago are partly filled with basalt. The Serenitatis Basin contains a succession of layered extrusive units tha t are collectively 2 to 4 km thick, 750 km in diameter, and 300,000 to 500,000 km in volume. Some giant impact basins are also associated with antipodal features caused by propagation of compressive waves through the planetary interior. These features include hilly, lineated, and jumbled terrain, as observed in areas antipodal to the Caloris Basin on Mercury. Swirled terrain and remnant paleomagnetism are observed on the Moon in areas antipodal to the Imbrium Basin. In addition, some recent features on the Moon, such as Ina, antipodal to the South Pole-Aitken Basin, are inferred to have been caused by degassing of volatiles (important materials for sustaining human settlement) in areas of weak and fractured crust.

This articles is adapted from oral presentation at AAPG Convention, Denver, Colorado, June 7-10, 2009.

Water ice and other volatiles are not only vital to sustaining human settlement in space, but hydrogen and oxygen extracted fro m water by hydrogen-oxide reactions can also be used as propellants on interplanetary missions. Water ice occurs in abundance on Mars in polar ice caps, as well as in shallow permafrost. Martian polar caps, 2.7 and 3.1 km thick at the north and south poles, respectively, have an ice core overlain by carbon dioxide frost that sublimates during spring. The ice layers are interbedded with numerous thin dust layers that record global cycles of dust storms. Martian permafrost, which appears to hold more water ice than the poles, occurs in a wide variety of forms, including collapse structures, polygonal terrain, and pingoes with morphologies similar to those of terrestrial periglacial features.

Water ice may also occur on the Moon at the north and south poles, judging from hydrogen neutron scattering signatures from Clementine and Lunar Prospector missions. Given radar reflectivity signatures, lunar ice probably does not occur in extensive sheets at the surface, but, rather, in disseminated form in the shallow (<40 cm) regolith in floors of permanently shadowed craters. Estimates of the ice resource, hypothesized to have accumulated from meteoritic and cometary impacts, range from 10 to 300 million metric tons (3 to 90 billion gallons). An important objective of the Lunar Reconnaissance Orbiter mission, planned for launch in 2009, will be to map the distribution of, and quantify, the lunar ice resource.

This articles is adapted from oral presentation at AAPG Convention, Denver, Colorado, June 7-10, 2009.

Although only 17% of the entire lunar surface is covered by basalt and underlying associated magma cooling units, ~60% of the western hemisphere on the lunar nearside contains magmatic complexes emplaced in numerous episodes ranging from approximately 3.75 Ga (billion years ago) to possibly as recently as 0.9 Ga, inferred from crater counts and overlapping relationships between lava- flow units and bright rays associated with Copernican-age craters. Oceanus Procellarum contains the largest continuous extent of lunar basalts on the Moon, and its upper fill is a complex of at least four different flow units, recognized on the basis of albedo and spectral reflectivity. Individually, these flow units are only a few hundreds of meters th ick, but may be underlain by 2-4 km thick basi n-filling units. Oceanus Procellarum has been interpreted by some authors as the western part of the 2400-km-wide Gargantuan Basin, inferred to have formed from a giant impact ~4.3 Ga. Gargantuan Basin lacks a surrounding mountain rim and underlying mascon, features commonly associated with other nearside lunar basins such as Mare Tranquillitatis, Serenitatis, and Crisium. However, the absence of these features may be due to the Gargantuan Basin having formed so early that the lunar crust may have not been sufficiently rigid to support rim material and excess masses of thick basin-filling units.

Presented by William A. Ambrose, Bureau of Economic Geology John A. and Katherine G. Jackson School of Geoscience, at the 2008 AAPG International Convention Cape Town, South Africa October 27, 2008.